This spring,my neighbor poured a slab for an addition over “R-10” bubble pack. He was taken aback when I told him that the claimed insulating value of this product was open to question.Advertisements and Internet sites have quoted values as high as R-15 for two layers of plastic bubbles and a layer or two of foil. Building science and some test data have shown these products to have an R-value closer to 1 or 2. Last September, the editors of Energy Design Update (EDU) questioned the astounding claims for R-value made by various manufacturers and distributors of foil-faced bubble pack insulation. Curiously, the November issue of EDU was full of qualifications from manufacturers, downrating their R-value claims.To help resolve these competing claims, Canada Mortgage and Housing Corporation (CMHC) decided to fund a quick study on the actual installed performance of foil bubble pack and competing subslab insulations. Four new houses in southwestern Ontario were tested in the winter and spring of 2004. Each house had two sets of four resistance temperature detectors (RTD) stacked vertically to measure the thermal gradient from the top of the slab ...